Hot-box detector



Jan. 31, 1961 HOT-BOX DETECTOR Filed June 27, 1955 ik?! d U...

ATTORNEYS F. G. wlLLEY 2,970,210

HOT-BOX DETECTOR Frank G.` Willey, Roslyn I'Ieights,`l\l.Y.,` assignor toServo l Corporation of America, New Hyde Park, NX., a corporation of New York Filed June 27, 1955, Ser. No. 518,251

3 Claims. (Cl. 246-169) This invention relates to` trackside-mounted:"hot-box detector equipment,` for` use in detecting overheated journal-end conditions before achievement of a temperature considered dangerous to the safety of a passing railroad train. This application is directed to improvements over particularly in the varieties disclosed in said copending applications, auxiliary mechanisms and devices are required in addition to the rails at the hot-box detector loca tion. These devices may be'mounted,inconspicuously, but they remain items of additional equipment and, as

such, they are subject to special maintenance and in many cases may project in the way of parts that maybedragged by a passing train.

It is, accordingly, an object to provide an improved hot-box detector requiring no special auxiliary means capable of presenting a hazard to parts or the like dragged by a passing train.

It :is a further object to provide a hot-box detector more readily maintained by existing methods, practices, and personnel.

It is also an object to provide an improved" hot-box detector lending itself particularly to incorporation along a railroad right of ywayl that is protected by a block-signaling system.

Other objects and various further features `of novelty i and invention will be pointed out or will `occur to those skilled in the art from a reading of the specification in conjunction with the accompanying drawings.

preferred form of the invention:

`Fig-l is an electrical diagram `schematically showing -components of the hot-box detector of the invention; and

the horizontal elevation of passing journal endsand the `trip means functions substantially only when `a journal end is in the response eld of the detector cell, thus precluding the possibility of cell response to undesired heat sources, such as brakeshoes, hoses, and the'like. My trip mechanism employs insulated rail sections on opposite sides of the track, said rail sections longitudinally overlapping only essentially for the distance represented by the effective width of a journal box, or at least no greater than a wheel diameter, so as to preclude response to brakeshoes. By eiective width is meant that portion of the journal box which is viewed by the cell. The mechanism may be part of a shutter-operating circuit, completed only when both wheels of a given axle contact the respective overlapping parts of said rails; in the form In said `drawings, which show, for illustrative purposes only, a

Ynited States Patent' shown,'theshutter means is merely a relay which Aconnects the output of the cell to a thresholdsresponsive circuit element, thethresholdbeing determined in advance to reliect a detected heat signal exceeding a predetermined safety'limit of journal-end temperature.

In application to block signaling systems, wherein all rail sections on one side of the track are electrically connected, and wherein all rail sections onthe other side of `the track are electrically interconnected, I install my` trip mechanism by electrically by-passing the two rail sections which overlap at the trackside location of the detector. In

this way, the rail sections for the trip remain electrically insulated, and the normal functioning of the block signaling system is otherwise unaliected If desired, power may be` conserved and spurious response avoided by activating the local power supply to the detector only inresponse to -a control, signal supplied from the local block of the bl0ck signaling system.

Referring to the drawings, my invention is shown in application to a railroad right of way, including standard rail sections 1011`12 (of length a) on one side of the track, and standard rail sections 13-14-15 (of length a) on the other side of the track. The detector may be mounted trackside withina permanent housing 16 and is preferably provided in duplicate on opposite sides of the track atsaid location 17, as disclosed in said copending applications. The detector may include a heat-responsive cell 18 directionally aligned for response at substantially the horizontal elevation of passing journal ends; which for standard passenger and freight-car wheels will be" l5 to 18 inches above railhead. I indicate at ,19 my preference for employing infrared-transmitting optics on the response alignment 20 of the cell 18, thus more clearly localizing all response to a field corresponding to a part of a journal end. In Fig. 2, the optics 19 is shown protected by a hood 21, and these parts constitute essentially the only exposed parts of the device.

The detector cell may be one of a number of Varieties, but I indicate my preference for employing a flake of so-called thermistor material, and I have shown provision of a second Hake 22, shielded by means 23 and acting as a compensator in'a bridge-connected employment of the cells 18-22. The cells may be biassed by means 24-25, and the signal1 output is` processed by first: and `second ampliers-26`-27 for application to threshold-responsive means, suchias a relay having a coil 28 and normallyopen contacts 29-30. 'The contacts 29 servea hold-in` funcl onceahot-box signal above threshold has beenrdetected,

and the contacts 30 control the activation of alarm-means .31 and signaling means 32. The signaling means` may be for remote indication, employing techniques `known to those skilled in the art, but inthe form shown I provide a simple local signal lamp 33 at housing 16said signal lamp being hooded for projection up and down the length of track, for ready inspection or spotting by `train personnel. If` desired, the signaling means 32-33 may incorporate keying mechanism, whereby the visual indication at 33 may be clearly recognized and distinguished from track-switch lamps and the like.

In accordance with the inventionVtrip `signals controlling the shutter operation of thedetector mayemploy two insulated rail sections 35-36 on opposite sides of the track at the location 17, and said rail sections 35-36 longitudinally overlap by the amount d. The amount d will be understood to represent a distance of the order of the width of a journal box, or at least a distance not exceedingthe diameter of a standard wheel, whereby trip functioning may be avoided during cell exposure to a brakeshoe. In order to preserve existing installations of standard rail lengths, the insulated rail sections 35-36 may be cut from standard rails, so that the remainder sec- 3 tions 35'-36 will be of a supplementary length. Thus, the combined length (b4-c) of sections .3S-35', and the combined length of sections 36-36', will be understood to be standard and preferably equal to'the length a of i any of the rail sections`10-11-12 and '13-14-15 V'I'he combined lengths b of the insulatedl section 35-36 will preferably be less thanthe minimum axle spacing of standard trucks, so that faulty tripping occasioned by adjacent axles of the same truck may be avoided.

`Electrical insulation of the sections 35-36 may be achieved by employing insulated connectors or fish plates 38-39 at the insulated joints, and jumpers 404-41 may bridge or by-pass the insulated rail sections,by continuously electrically connecting section 11 to section 35', and section 36' to section 1K4, respectively. Block-signal operation in the normal manner may thus be unaffected by my trip mechanism.

The trip circuit including rail sections 35--36 may control a mechanical shutter or other means capable of determining the admission of radiant energy to the cell 18, but I indicate my preference for accomplishing this func- .tion electrically and have employed a single-pole relay 42 which will be caused to close and thus complete the circuit from amplifier 27 to threshold-responsive means 28 only when a journal end is in the responsive eld of the .cell 18. In the form shown, power for operating the amplifiers 26-27, the relays 42-28, and the external signal means 31-32, is derived from a local source 43, and this power may be conserved by energizing these various devices only when a train is in the local block which encompasses the location 17. Thus, I have shown a local relay 46 energized by the local block-signaling circuitry (not shown) so as to close its contacts and to supply power to the various circuits in the local detector of Fig. 1 only when a train enters the local signal block. As each -axle passes Y the location 17, the trip relay 42 will function to deliver heat-signal output to the threshold circuit 28; If none of the heat signals exceeds threshold, there will be no further functioning of the device, but if threshold is exceeded, the contact 29 will serve to lock-in the alarm and signaling means S14-32. The train will then be presumably flagged to a stop, so that the trouble may be identitied and remedial measures undertaken. Alternatively, the signaling means 32 will be understood to include counting means, car-marking devices, and other more complex mechanisms described in said copending applications, whereby said axle location may be recorded (and, if desired, remotely transmitted) so that remedial measures may be taken at a convenient location with dispatch.

As a further feature, I illustrate at 47 a non-linear cou- Y pling between amplifiers 26-27. The element 47 may form part of an attenuator pad and be characterized by a negative temperature coeicient of resistance, the element crease. This corresponds with the fact that on hot days a smaller differential exists between ambient and marginally unsafe journal-box temperatures than on cold days.

It will be seen that I have described an improved and relatively simple hot-box detector equipment characterized particularly by ease of maintenance, in that standard block signaling techniques are employed at the detector installation. Furthermore, my arrangement requires no auxiliary devices near or between the tracks, so that no obstructions are presented to parts or other matter dragged by a passing train. My system is easily integrated into existing block signaling systems, and my ar rangement of switches is such as to promote economical use of local power supplies and avoidance of spurious signals. In particular, my device is essentially tamperproof and may be rugged and inconspicuous except for such alarms and warning signals as it is able to develop.

While I have described the invention in detail for the preferred form-shown, it will be understood that modifications may be made within the scope of the invention as defined in the claims which follow.

I claim:

l. In a railroad hot-box detecting system including a normally inactive means including a heat-responsive cell mounted alongside a railroad track right of way and directionally aligned to observe passing journal boxes, means for activating said normally inactive means only when said journal boxes are in the ield of view of said cell, comprising two electrically insulated longitudinally olif-set rail sections at opposite sides of said right of way and having an overlap substantially equal to the effective width of a journal box, a control circuit completed only when opposite wheels of a railroad car are on the overlapping parts of said rail sections for activating said cell, and signal output means responsive to the output of said cell.

2.l A detector according to claim l, in which said signal-output means includes threshold-responsive alarm means, whereby an alarm is developed for signals exceeding threshold.

3. A detector according to claim 1, in which said signal-output means includes threshold-responsive signalling means, whereby a warning-signal indication may be developed for detector signals exceeding threshold.

l References Cited in lthe le of this patent UNITED STATES PATENTS 431,408 Snee July 1,-1890 1,149,787 Sebok Aug. 10, 1915 1,379,166 Case May 24, 1921 1,484,943 Hall Feb. 26, 1924 1,496,194 Ziegler June 3, 1924 1,702,997 Ewing Feb. 19, 1929 1,791,938 Schroeter et al Feb. 10, 1931 1,810,211 yHershey June 16, 1931 1,835,234 McKeen Dec. 8, 1931 1,951,426 Littler Mar. 20, 1934 2,031,789 Pierce Feb. 25, 1936 2,133,687 Drake Oct. 18, 1938 2,376,162 Merriman May 15, 1945 2,423,885 Hammond July 15, 1947 2,560,753 Weinberg July 17, 19'51 2,628,344 Johnson Feb. 10, 1953 2,699,834 OBrien Jan. 18, 1955 2,721,934 Shepardson Oct. 25, 1955 2,818,508 Johanson Dec. 31, 1957 

